Touch-Sensitive Device

1. A touch-sensitive device, comprising: a light source for emitting light into a touch-sensitive waveguide, the touch-sensitive waveguide comprising side parts and a touch-sensitive surface extending between the side parts of the touch-sensitive waveguide, the touch-sensitive waveguide being configured for guiding light from the light source towards the touch-sensitive surface of the touch-sensitive waveguide in such a way that at least part of the guided light may be disturbed by an object at a contact point where the object contacts the touch-sensitive surface, a detector array configured for detecting intensity distribution of light having propagated from the light source through the touch-sensitive waveguide for position encoding the contact point between the object and the touch-sensitive surface, and a first light redirecting member and a second light redirecting member included in at least two of the side parts of the touch-sensitive waveguide, the first light redirecting member and the second light redirecting member being configured for redirecting light having propagated from the light source through the touch-sensitive waveguide and to at least one of the light redirecting members towards the detector array, such that the redirection of light involves changing the direction of propagation in a plane parallel to the touch-sensitive surface, such that light from the first redirecting member and second redirecting member is incident on the detector array at different angles, the angles being defined in the plane parallel to the touch-sensitive surface, wherein at least a part of the light propagating towards a specific point of the detector array is prevented from being incident upon the specific point of the detector array when the object contacts the touch-sensitive surface at a corresponding specific contact point.

2. The touch-sensitive device according to claim 1 , wherein the light redirected by the two different light redirecting members is distinguished from each other at the detector.

3. The touch-sensitive device according to claim 1 , wherein the light source is a single light source.

4. The touch-sensitive device according to claim 1 , wherein the light source is positioned at one corner of the device.

5. The touch-sensitive device according to claim 1 , wherein the detector is a single detector.

6. The touch-sensitive device according to claim 4 , wherein the detector is positioned at another corner of the device opposite the light source.

7. The touch-sensitive device according to claim 1 , wherein the first light redirecting member and the second light redirecting member are opposite each other.

8. The touch-sensitive device according to claim 1 , wherein the first light redirecting member and the second light redirecting member intersect in one corner of the device.

9. The touch-sensitive device according to claim 1 , wherein the device further comprises a third light redirecting member and a fourth light redirecting member included in at least additional two of the side parts of the touch-sensitive waveguide, at least one of the third light redirecting member and the fourth light redirecting member being configured for redirecting light having propagated from the at least first redirecting member and second redirecting member through the touch-sensitive waveguide and towards the detector array.

10. The touch-sensitive device according to claim 1 , wherein the touch-sensitive waveguide is a planar waveguide.

11. A method of position encoding an object contacting a touch-sensitive surface, the method comprising: emitting light from a light source into a touch-sensitive waveguide comprising side parts and the touch-sensitive surface extending between the side parts of the touch-sensitive waveguide, guiding light from the light source towards the touch-sensitive surface of the touch-sensitive waveguide, using the touch-sensitive waveguide, in such a way that at least part of the guided light may be disturbed by the object at a contact point where the object contacts the touch-sensitive surface, detecting, using a detector array, intensity distribution of light having propagated from the light source through the touch-sensitive waveguide for position encoding the contact point between the object and the touch-sensitive surface, and redirecting light having propagated from the light source through the touch-sensitive waveguide and to a first light redirecting member and a second light redirecting member included in at least one of the side parts of the touch-sensitive waveguide towards the detector array using at least one of the first light redirecting member and the second light redirecting member, such that the redirected light changes the direction of propagation after having propagated in the waveguide, whereby light from the first redirecting member and second redirecting member is incident on the detector array at different angles, the angles being defined in the plane parallel to the touch-sensitive surface, wherein at least a part of the light propagating towards a specific point of the detector array is prevented from being incident upon the specific point of the detector array when the object contacts the touch-sensitive surface at a corresponding specific contact point and with the redirecting members configured so that at least part of the guided light after having been redirected by the redirecting members changes between being prevented from being disturbed and being disturbed by the object at a contact point.